1. Field of the Invention
The present invention relates to the field of electro-chemical plating and, more particularly, to an electroplating apparatus including an in-line, real-time feedback system for uniformly electroplating metals on a semiconductor substrate.
2. Description of the Prior Art
In the fabrication of a semiconductor integrated circuit, metals are electro-chemically deposited onto a semiconductor substrate in order to electrically interconnect components in the integrated circuit. Typically, the substrate with a seed layer is positioned in an electroplating reactor vessel containing plating solution. At the bottom of the electroplating reactor vessel, an anode is provided for creating a desired electrical potential at the surface of the substrate.
For years, many attentions have been directed to the variations in current density across the surface of the substrate immersed in the plating solution during electroplating. Efforts to improve uniformity of electroplated metal layers include flow-controlling devices such as diffusers positioned within the electroplating reactor vessel for directing the flow of the electroplating solution. In some cases, uniformity of metal deposition is improved by using a segmented anode array including a plurality of concentric anode segments, which are operated independently at different electrical potentials.
However, the aforesaid prior art methods and/or apparatuses are still not satisfactory yet due to the fact that the metal depositing conditions are not controlled in real time.